Illumination device and display device

ABSTRACT

Provided is an illumination device that makes it possible to enhance utilization efficiency of light, and a display device that includes the illumination device. The illumination device includes: a light source that is configured to generate light of a first wavelength; a luminescent body that is configured to wavelength-convert the light of the first wavelength to light of a second wavelength, the second wavelength being different from the first wavelength; and a wavelength selective filter that is provided on a light-incident side of the luminescent body, the wavelength selective filter being configured to transmit the light of the first wavelength and to reflect the light of the second wavelength.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 15/484,541 filed on Apr. 11, 2017 which is a continuation ofU.S. patent application Ser. No. 14/439,873 filed on Apr. 30, 2015,issued on May 23, 2017 as U.S. Pat. No. 9,657,920, which is a nationalphase entry under 35 U.S.C. § 371 of International Application No.PCT/JP2013/077449, filed Oct. 9, 2013, published on May 15, 2014 as WO2014/073313 Al, which claims priority from Japanese Patent ApplicationNo. JP 2012-247262 filed in the Japanese Patent Office on Nov. 9, 2012.

TECHNICAL FIELD

The present disclosure relates to an illumination device suitable for asurface light source, and a display device including this.

BACKGROUND ART

In an illumination device used in a backlight of a liquid crystaldisplay device, or the like, there has been known an edge-typeconfiguration in which, for example, a light source is disposed in thevicinity of a side surface (a light-incident surface) of a light guideplate. In the edge-type illumination device, light from the light sourceis allowed to enter the side surface of the light guide plate and toemit through a front surface of the light guide plate.

For example, Patent Literature 1 describes a dichroic mirror surroundingrearward of a cold cathode tube as a light source, in order to restraindegradation of the light guide plate. The dichroic mirror selectivelytransmits ultraviolet rays and selectively reflects at least visiblerays. Behind the dichroic mirror, an ultraviolet ray absorption sheet isprovided, and ultraviolet rays that have passed through the dichroicmirror are absorbed.

CITATION LIST Patent Literature

Patent Literature 1: JP 2010-157468A

SUMMARY OF INVENTION

In an illumination device, in general, it is desirable to improveefficiency of utilizing light.

It is therefore desirable to provide an illumination device that makesit possible to improve efficiency of utilizing light, and a displaydevice including this.

An illumination device according to an embodiment of the presentdisclosure includes: a light source that is configured to generate lightof a first wavelength; a luminescent body that is configured towavelength-convert the light of the first wavelength to light of asecond wavelength, the second wavelength being different from the firstwavelength; and a wavelength selective filter that is provided on alight-incident side of the luminescent body, the wavelength selectivefilter being configured to transmit the light of the first wavelengthand to reflect the light of the second wavelength.

In the illumination device according to the embodiment of the presentdisclosure, the light of the first wavelength from the light sourcepasses through the wavelength selective filter and travels toward theluminescent body. The light that collides with the luminescent body iswavelength-converted by the luminescent body to become the light of thesecond wavelength. The light that does not collide with the luminescentbody passes as it is.

Here, the wavelength selective filter is configured to transmit thelight of the first wavelength and to reflect the light of the secondwavelength. This allows the light of the first wavelength generated fromthe light source to transmit the wavelength selective filter with littleattenuation. Moreover, of the light of the second wavelength that hascollided with the luminescent body and has been wavelength-converted,light travelling rearward is reflected by the wavelength selectivefilter, is radiated forward as reflected light, and is utilizedeffectively.

A display device according to an embodiment of the present disclosure isprovided with a liquid crystal panel and an illumination device on arear side of the liquid crystal panel, the illumination deviceincluding: a light source that is configured to generate light of afirst wavelength; a luminescent body that is configured towavelength-convert the light of the first wavelength to light of asecond wavelength, the second wavelength being different from the firstwavelength; and a wavelength selective filter that is provided on alight-incident side of the luminescent body, the wavelength selectivefilter being configured to transmit the light of the first wavelengthand to reflect the light of the second wavelength.

In the display device according to the embodiment of the presentdisclosure, the light of the first wavelength or the light of the secondwavelength from the illumination device is transmitted selectively bythe liquid crystal panel. Thus, image display is performed.

According to the illumination device of the embodiment of the presentdisclosure, the wavelength selective filter is provided on thelight-incident side of the luminescent body. The wavelength selectivefilter is configured to transmit the light of the first wavelength andto reflect the light of the second wavelength. Hence, it is possible toimprove efficiency of utilizing light. Configuration of a display devicewith the illumination device makes it possible to reduce powerconsumption.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an overall configuration of a main partof an illumination device according to a first embodiment of the presentdisclosure.

FIG. 2 is a diagram schematically illustrating a transmissioncharacteristic of a wavelength selective filter illustrated in FIG. 1.

FIG. 3 is a diagram schematically illustrating a reflectioncharacteristic of the wavelength selective filter illustrated in FIG. 1.

FIG. 4 is a diagram schematically illustrating a transmissioncharacteristic of a wavelength selective filter in a display deviceapplication.

FIG. 5 is a diagram schematically illustrating a reflectioncharacteristic of the wavelength selective filter in the display deviceapplication.

FIG. 6 is a cross-sectional view illustrating, in an enlarged manner, anexample of an arrangement relation of a luminescent body and thewavelength selective filter illustrated in FIG. 1.

FIG. 8 is a cross-sectional view illustrating another example of thearrangement relation of the luminescent body and the wavelengthselective filter illustrated in FIG. 1.

FIG. 7 is a diagram illustrating action of the illumination deviceillustrated in FIG. 1.

FIG. 9 is a cross-sectional view illustrating, in an enlarged manner, anexample of the arrangement relation of the luminescent body and thewavelength selective filter in an illumination device according to asecond embodiment of the present disclosure.

FIG. 10 is a cross-sectional view illustrating another example of thearrangement relation of the luminescent body and the wavelengthselective filter illustrated in FIG. 9.

FIG. 11 is a perspective view illustrating an overall configuration ofan illumination device according to a third embodiment of the presentdisclosure.

FIG. 12 is a cross-sectional view illustrating an arrangement relationof a light source, the luminescent body, the wavelength selectivefilter, and a light guide plate illustrated in FIG. 11.

FIG. 13 is a diagram illustrating action of the illumination deviceillustrated in FIG. 11.

FIG. 14 is a perspective view illustrating a bundle of rays travellingfrom the light source toward a light-incident surface of the light guideplate illustrated in FIG. 13.

FIG. 15 is a cross-sectional view illustrating an arrangement relationof the light source, the luminescent body, the wavelength selectivefilter, and the light guide plate in a modification example 2.

FIG. 16 is a perspective view illustrating an appearance of a displaydevice according to a fourth embodiment of the present disclosure.

FIG. 17 is an exploded perspective view of a main body illustrated inFIG. 16.

FIG. 18 is an exploded perspective view of a panel module illustrated inFIG. 17.

FIG. 19 is a perspective view illustrating an appearance, viewed on afront side, of an application example 1 of the display device accordingto the above-mentioned example embodiment.

FIG. 20 is a perspective view illustrating an appearance, viewed on arear side, of the application example 1 of the display device.

FIG. 21 is a perspective view illustrating an appearance, viewed on afront side, of an application example 2 of the display device.

FIG. 22 is a perspective view illustrating an appearance, viewed on arear side, of the application example 2 of the display device.

FIG. 23 is a perspective view illustrating an appearance, viewed on afront side, of an application example 3 of the display device.

FIG. 24 is a perspective view illustrating an appearance, viewed on arear side, of the application example 3 of the display device.

FIG. 25 is a perspective view illustrating an appearance of anapplication example 4 of the display device.

FIG. 26 is a perspective view illustrating an appearance of anapplication example 5 of the display device.

FIG. 27 is a perspective view illustrating an appearance of anapplication example 6 of the display device, in a closed state.

FIG. 28 is a perspective view illustrating an appearance of theapplication example 6 of the display device, in an opened state.

FIG. 29 is a perspective view illustrating an appearance of anapplication example 7 of the illumination device.

FIG. 30 is a perspective view illustrating an appearance of anapplication example 8 of the illumination device.

FIG. 31 is a perspective view illustrating an appearance of anapplication example 9 of the illumination device.

DESCRIPTION OF EMBODIMENTS

In the following, some embodiments of the present disclosure will bedescribed in detail with reference to the drawings. It is to be notedthat the order of description is as follows.

1. First Embodiment (an illumination device; an example in which awavelength selective filter is provided on a light-incident side of aluminescent body)

2. Modification Example 1 (an illumination device; an example in whichthe luminescent body includes a sulfide phosphor)

3. Second Embodiment (an illumination device; an example in which asurface on which the wavelength selective filter is provided of thecontainer is curved convexly toward a light source)

4. Third Embodiment (an illumination device; a backlight)

5. Modification Example 2 (an illumination device; a combination of thesecond and the third embodiments)

6. Fourth Embodiment (a display device; a liquid crystal display device)

7. Electronic Apparatus (application examples of the display device)

8. Illumination Apparatus (application examples of the illuminationdevice)

(First Embodiment)

FIG. 1 illustrates an overall configuration of a main part of anillumination device according to a first embodiment of the presentdisclosure. The illumination device 1 may be used as a backlight thatilluminates a transmissive liquid crystal panel from behind, or as anillumination apparatus indoors or the like, and may include, forexample, a light source 10, a luminescent body 20, and a wavelengthselective filter 30.

In the present embodiment, in an arrangement direction A1 of the lightsource 10, the luminescent body 20, and the wavelength selective filter30, a direction from the light source 10 toward the luminescent body 20is referred to as forward A1F, while a direction from the luminescentbody 20 to the light source 10 is referred to as rearward A1R.

The light source 10 is configured to generate light v11 and v12 of aspecific wavelength (a first wavelength λ1). The light source 10 may be,for example, a point light source, and specifically, may be configuredof an LED (Light Emitting Diode).

The luminescent body 20 may include a luminescent body having a functionof wavelength conversion, for example, a phosphor (a fluorescentsubstance) such as a fluorescent pigment or a fluorescent dye, or aquantum dot. The luminescent body 20 is configured to be excited by thelight v11 and v12 of the first wavelength, and to produce light bywavelength-converting the light v11 and v12 of the first wavelength tolight v21 of another wavelength (a second wavelength λ2) different fromthe first wavelength, by a principle of fluorescence emission or thelike. In FIG. 1, the light v11 and v12 of the first wavelength isdenoted by a solid line while the light v21 of the second wavelength isdenoted by a dashed line.

The first wavelength λ1 and the second wavelength λ2 are not limited inparticular; for example, in a case of a display device application, thelight v11 and v12 of the first wavelength may be blue light (of awavelength of, for example, about 440 to 460 nm both inclusive), whilethe light v21 of the second wavelength may be red light (of a wavelengthof, for example, about 620 nm to 750 nm both inclusive), or green light(of a wavelength of, for example, about 495 nm to 570 nm bothinclusive). In other words, the light source 10 may be a blue lightsource, and the luminescent body 20 is configured to wavelength-convertblue light to red light or green light.

The luminescent body 20 may preferably include a quantum dot. A quantumdot is a particle having a longer axis of about 1 nm to 100 nm bothinclusive, and has discrete energy levels. Since an energy state of aquantum dot depends on its size, a change in size allows a free choiceof a wavelength of light emission. Moreover, light emitted by a quantumdot has a narrow spectrum width. Combination of light having such steeppeaks allows expansion of a color gamut. Accordingly, the use of aquantum dot for the luminescent body 20 makes it possible to easilyexpand a color gamut. Furthermore, a quantum dot has a high responsespeed, making it possible to utilize effectively light from the lightsource 10. In addition, a quantum dot has high stability. A quantum dotmay be, for example, a compound of a group 12 element and a group 16element, a compound of a group 13 element and a group 16 element, or acompound of a group 14 element and a group 16 element. Examples mayinclude CdSe, CdTe, ZnS, CdS, PbS, PbSe, Cd HgTe, and so forth.

It is to be noted that FIG. 1 represents the luminescent body 20 as aparticle like a quantum dot for simplicity. However, it goes withoutsaying that the luminescent body 20 is not limited to a particle.Moreover, FIG. 1 represents a region in which the luminescent body 20 isdisposed (hereinafter referred to as a luminescent body disposed region21) by surrounding it by a dotted line.

The wavelength selective filter 30 is provided on a light-incident side20A of the luminescent body 20, and is configured to transmit the lightv11 and v12 of the first wavelength and to reflect the light v21 of thesecond wavelength. Thus, in the illumination device 1, it is possible toimprove efficiency of utilizing light.

Here, the light-incident side 20A of the luminescent body 20 refers to aspecial region on the rearward AIR side (on the light source 10 side) inthe arrangement direction A1, compared to the luminescent body disposedregion 21. Specifically, the light-incident side 20A of the luminescentbody 20 refers to between the light source 10 and the luminescent bodydisposed region 21.

FIG. 2 schematically illustrates an example of a transmissioncharacteristic 30T of the wavelength selective filter 30. FIG. 2represents a spectrum SB of blue light as well. As illustrated in FIG.2, in a case that the light v11 and v12 of the first wavelength is, forexample, blue light, the wavelength selective filter 30 may have hightransmissivity in a wavelength range of, for example, about 500 nm orless that includes a wavelength band of blue light.

FIG. 3 schematically illustrates an example of a reflectioncharacteristic 30R of the wavelength selective filter 30. FIG. 3represents a spectrum SG of green light as well. As illustrated in FIG.3, in a case that the light v21 of the second wavelength is, forexample, green light, the wavelength selective filter 30 may have highreflectivity in a wavelength range of, for example, about 500 nm or morethat includes a wavelength band of green light.

FIGS. 4 and 5 schematically illustrate an example of a transmissioncharacteristic 30TD and a reflection characteristic 30RD, respectively,of the wavelength selective filter 30 in a display device application.FIGS. 4 and 5 represent a spectrum SR of red light, the spectrum SG ofgreen light, and the spectrum SB of blue light as well. As illustratedin FIGS. 4 and 5, the wavelength selective filter 30 may have hightransmissivity in a wavelength range of, for example, about 500 nm orless that includes the light v11 and v12 of the first wavelength, thatis, the wavelength band of blue light. The wavelength selective filter30 may have high reflectivity in a wavelength range of, for example,about 500 nm or more that includes the light v21 of the secondwavelength, that is, the wavelength band of red light or green light.

The wavelength selective filter 30 as described above may be configuredof, for example, a dielectric multilayer film. Specifically, thewavelength selective filter 30 may have a structure of lamination of anumber of dielectric layers having thicknesses of about ¼ (a quarter) ofthe second wavelength and having different refractive indexes from oneanother. Thus, the wavelength selective filter 30 is configured toreflect selectively the light v21 of the second wavelength and totransmit selectively the light v11 and v12 of the first wavelength.

FIG. 6 illustrates, in an enlarged manner, an example of an arrangementrelation of the luminescent body 20 and the wavelength selective filter30 illustrated in FIG. 1. The luminescent body 20 may preferably beaccommodated and sealed in a tubular container (capillary) 22 made ofglass or the like. This makes it possible to restrain characteristicchanges of the wavelength conversion member 30 due to moisture or oxygenin the air and to facilitate handling.

The container 22 may have a shape of a cuboid (including a shape thatcan be called a substantially cuboid even if there is a subtledeformation such as a rounded side or the like). The container 22 may bedisposed with a surface of the cuboid facing the light source 10. Thecontainer 22 may include, in its inside, a hollow part that serves as anaccommodating section 23 of the luminescent body 20. It goes withoutsaying that the accommodating section 23 corresponds to theabove-mentioned luminescent body disposed region 21.

Preferably, the wavelength selective filter 30 may be provided on anouter surface 22A on the light-incident side of the container 22. Thisis because, since the luminescent body 20 is a diverging light source,it is desirable that the wavelength selective filter 30 be disposed at aclose distance from the luminescent body 20, in order to further improveefficiency of utilizing light. Moreover, it is possible to eliminate agap between the container 22 and the wavelength selective filter 30,making it possible to reduce light leaks and to restrain lowering ofefficiency of utilizing light. Furthermore, coating on glass is easy,making it possible to form the wavelength selective filter 30 easily.

A width W30 of the wavelength selective filter 30 may be preferablylarger than a width W23 of the accommodating section 23. This makes itpossible to reduce the light of the first wavelength that passes througha glass part 22B of the container 22 without passing through theaccommodating section 23, leading to enhanced color uniformity in aplane.

The wavelength selective filter 30 may be preferably provided at leaston a surface 22C that faces the light source 10 of the container 22. Inthis way, the width W30 of the wavelength selective filter 30 becomesequal to or substantially equal to a value obtained by adding twice of athickness T22 of the container 22 to the width W23 of the accommodatingsection 23. Accordingly, it is possible to make the width W30 of thewavelength selective filter 30 larger than the width W23 of theaccommodating section 23 securely.

Furthermore, the wavelength selective filter 30 may preferably extend,as illustrated in FIG. 7, beyond the surface 22C that faces the lightsource 10 of the container 22, on at least part (part or all) ofsurfaces 22D and 22E adjacent to the facing surface 22C. This makes itpossible to capture light that travels around the adjacent surfaces 22Dand 22E.

The luminescent body 20 and the wavelength selective filter 30 that areillustrated in FIG. 6 or 7 may be manufactured, for example, as follows.

First, for example, a fluorescent substance or a quantum dot is kneadedinto a ultraviolet curing resin. A mixture thus obtained is put in thecontainer 22 such as a glass tube, and one end of the container 22 issealed. The resin is cured by ultraviolet irradiation, to form theluminescent body 20 in a resin form having viscosity to some extent.Subsequently, a dielectric multilayer film is coated by sputtering onthe outer surface 22A on the light-incident side of the container 22, toform the wavelength selective filter 30. At this occasion, a surfacetreatment of the glass tube of the container 22 is unnecessary; washingits surfaces may be enough.

In the illumination device 1, the light source 10 generates the lightv11 and v12 of the first wavelength. The light v11 and v12 passesthrough the wavelength selective filter 30 and travels toward theluminescent body 20. The light v12 that collides with the luminescentbody 20 is wavelength-converted by the luminescent body 20 to become thelight v21 of the second wavelength. The light v11 that does not collidewith the luminescent body 20 passes as it is.

Here, the wavelength selective filter 30 is configured to transmit thelight v11 and v12 of the first wavelength and to reflect the light v21of the second wavelength. This allows the light v11 and v12 of the firstwavelength generated from the light source 10 to transmit the wavelengthselective filter 30 with little attenuation and to travel toward theluminescent body 20.

When the light v12 collides with the luminescent body 20, as illustratedin FIG. 8, the luminescent body 20 allows the wavelength-converted lightv21 of the second wavelength to be emitted omnidirectionally from theluminescent body 20. As the light v21, there may be light that isemitted from the luminescent body 20 at a substantially same angle asthat of light-incidence. On the other hand, as the light v22, there maybe a bundle of rays that is emitted rearward A1R (toward the wavelengthselective filter 30).

Here, the wavelength selective filter 30 is configured to transmit thelight v11 and v12 of the first wavelength and to reflect the light v21and v22 of the second wavelength. Therefore, the light v22 is reflectedby the wavelength selective filter 30, is radiated forward A1F asreflected light v23, and is utilized effectively.

As described above, in the present embodiment, the wavelength selectivefilter 30 is provided on the light-incident side 20A of the luminescentbody 20. The wavelength selective filter 30 is configured to transmitthe light v11 and v12 of the first wavelength and to reflect the lightv21 and v22 of the second wavelength. Hence, it is possible to allownearly half of the light that has been wavelength-converted by theluminescent body 20 to be reflected by the wavelength selective filter30, to alter the direction of their travel to allow them to be emittedforward A1F, and to improve efficiency of utilizing light.

Also, effective utilization of light leads to improvement in lightemission efficiency of the whole system, making it possible to enhancebrightness of the illumination device 1. Further, effective utilizationof light leads to improvement in light emission efficiency of the wholesystem, making it possible to reduce power for the light source 10,which contributes to lower power consumption of the illumination device1. In addition, effective utilization of light leads to improvement inlight emission efficiency of the whole system, making it possible toreduce the number of LEDs or the like that constitute the light source10, pursuing cost reduction.

In particular, the luminescent body 20 is accommodated in the container22, and the wavelength selective filter 30 is provided on the outersurface 22A on the light-incidence side of the container 22. Hence, itis possible to decrease a distance between the luminescent body 20 andthe wavelength selective filter 30, making it possible to reduce lightleaks and to further improve efficiency of utilizing light.

Moreover, in particular, the container 22 includes, in its inside, theaccommodating section 23 of the luminescent body 20, and the width W30of the wavelength selective filter 30 is larger than the width W23 ofthe accommodating section 23. Hence, it is possible to reduce leaks ofthe light v11 and v12 of the first wavelength, making it possible toenhance color uniformity in a plane.

MODIFICATION EXAMPLE 1

It is to be noted that, in the above-described first embodiment,description has been given on a case that the luminescent body 20includes a fluorescent substance or a quantum dot. However, theabove-described first embodiment may be suitably applied to a case thatthe luminescent body 20 includes a sulfide phosphor. A sulfide phosphorhas a property of being chemically unstable, easily deteriorated in theair, and difficult to handle. Accordingly, also in a case of using asulfide phosphor as the luminescent body 20, by sealing and closing theluminescent body 20 in the container 22 similarly to the above-describedfirst embodiment, it is possible to obtain effects of restrainingcharacteristic changes due to moisture or oxygen in the air andfacilitating handling.

Examples of sulfide phosphors that generate green light as the light v21of the second wavelength may include SrGa2S4:Eu (strontium thiogallate).Examples of sulfide phosphors that generate red light as the light v21of the second wavelength may include CaS:Eu (calcium sulfide).

(Second Embodiment)

FIG. 9 illustrates, in an enlarged manner, an example of an arrangementrelation of the luminescent body 20 and the wavelength selective filter30 in an illumination device 2 according to a second embodiment of thepresent disclosure. In the illumination device 2, the surface 22C thatfaces the light source 10 of the container 22 is curved convexly towardthe light source 10, enhancing a light condensing effect. Otherwise, theillumination device 2 has similar configurations, actions, and effectsto those of the above-described first embodiment. Therefore, descriptionwill be given with similar components denoted by similar referencenumerals.

The light source 10, the luminescent body 20, the luminescent bodydisposed region 21, and the wavelength selective filter 30 may beconfigured similarly to those of the first embodiment.

In the container 22, as mentioned above, the surface 22C that faces thelight source 10 is curved convexly toward the light source 10. In thisway, the inside surface of the facing surface 22C has a function as aconcave mirror, enhancing a light condensing effect and leading tofurther improvement in efficiency of utilizing light.

The wavelength selective filter 30 may be preferably provided on theouter surface 22A on the light-incident side of the container 22,similarly to the first embodiment.

The width W30 of the wavelength selective filter 30 may be preferablylarger than the width W23 of the accommodating section 23, similarly tothe first embodiment.

The wavelength selective filter 30 may be preferably provided at leaston the surface 22C that faces the light source 10 of the container 22,similarly to the first embodiment.

Furthermore, the wavelength selective filter 30 may preferably extend,as illustrated in FIG. 10, beyond the surface 22C that faces the lightsource 10 of the container 22, on part or all of the surfaces 22D and22E adjacent to the facing surface 22C. This makes it possible tocapture light that travels around the adjacent surfaces 22D and 22E.

In the illumination device 2, since the surface 22C that faces the lightsource 10 of the container 22 is curved convexly toward the light source10, the inside surface of the facing surface 22C has a function as aconcave mirror. Accordingly, the light v22 of the second wavelength isreflected by the wavelength selective filter 30, and the reflected lightv23 is easily condensed inward to be utilized more effectively.

(Third Embodiment)

FIG. 11 illustrates an overall configuration of an illumination deviceaccording to a third embodiment of the present disclosure. Theillumination device 3 may include, as its main part, the illuminationdevice 1 according to the first embodiment. In other words, theillumination device 3 may include a light guide plate 40, a reflectionmember 50, and an optical sheet 60, in addition to the light source 10,the luminescent body 20, and the container 22 on which the wavelengthselective filter 30 is provided, as described in the first embodiment.The light guide plate 40 corresponds to a specific example of “anoptical member” in the present disclosure.

In the present embodiment and later, a stacking direction of the opticalsheet 60, the light guide plate 40, and the reflection member 50 isreferred to as a Z direction (a front-rear direction). In a main surface(a largest surface) of the light guide plate 40, a horizontal directionis referred to as an X direction, and a vertical direction is referredto as a Y direction.

The light source 10 may be configured similarly to that of the firstembodiment. For example, the light source 10 may be sealed in a package11 (not illustrated in FIG. 11, refer to FIG. 12.), mounted on lightsource substrates 12, and disposed facing a light-incident surface 40Aof the light guide plate 40. The light source substrates 12 may have ashape of an elongated cuboid, and may be arranged in a line in alongitudinal direction of the light source substrates 12.

In an example illustrated in FIG. 11, the light-incident surface 40A maybe a right end surface and a left end surface of the light guide plate40. Accordingly, the arrangement direction A1, forward A1F, and rearwardA1R are directions parallel to the horizontal direction X in FIG. 11.

The luminescent body 20 and the wavelength selective filter 30 may beconfigured similarly to those of the first embodiment.

The light guide plate 40 is configured to guide the light from the lightsource 10 from the light-incident surface 40A toward a light-emissionsurface 40B. The light guide plate 40 may include mainly, for example, atransparent thermosetting resin such as a polycarbonate resin (PC) or anacrylic resin (for example, PMMA (polymethyl methacrylate)). The lightguide plate 40 may have a shape of a cuboid including a pair of mainsurfaces (a front surface and a bottom surface) that face in thefront-rear direction (the z direction) and four end surfaces (sidesurfaces) that are adjacent to them, that is, upper, lower, right, andleft end surfaces.

The right and the left end surfaces of the light guide plate 40 serve asthe light-incident surfaces 40A in which the light from the light source10 enters, as mentioned above. It is to be noted that the light-incidentsurfaces 40A may be only one of the right and the left end surfaces ofthe light guide plate 40. Alternatively, the light-incident surfaces 40Amay be three end surfaces, or all four end surfaces of the light guideplate 40.

The front surface of the light guide plate 40 may serve as thelight-emission surface 40B that allows the light that has enteredthrough the light-incident surface 40A to be emitted. The light-emissionsurface (the front surface) 40B and the bottom surface of the lightguide plate 40 may have a planar shape corresponding to, for example, anobject to be illuminated (for example, a liquid crystal panel 122, whichwill be described later) that is disposed on the light-emission surface40B side of the light guide plate 40.

The bottom surface 40D of the light guide plate 40 may be provided witha printed pattern having irregular reflection characteristics (notillustrated in FIG. 11, refer to FIG. 13.) This pattern is configured toallow the light travelling toward the bottom surface 40D of the lightguide plate 40 to be reflected toward the light-emission surface 40B ofthe light guide plate 40.

The reflection member 50 may be a plate-shaped or sheet-shaped memberprovided on the bottom surface 40D side of the light guide plate 40. Thereflection member 50 is configured to allow the light leaking, from thelight source 10, on the bottom surface 40D side of the light guide plate40 or the light emitted, from inside of the light guide plate 40, on thebottom surface 40D side to return toward the light guide plate 40. Thereflection member 50 may have functions of, for example, reflection,diffusion, scattering, or the like. This makes it possible to utilizethe light from the light source 10 effectively, leading to enhancedfront luminance.

The reflection member 50 may be configured of, for example, foamed PET(polyethylene terephthalate), a silver-evaporated film, a multilayerreflection film, or white PET. In a case that the reflection member 50is provided with a function of regular reflection (mirror reflection), asurface of the reflection member 50 may be preferably surface-treated bysilver evaporation, aluminum evaporation, multilayer film reflection, orthe like. In a case that the reflection member 50 is provided withminute shapes, the reflection member 50 may be integrally formed bytechniques such as heat press molding or melt extrusion molding using athermosetting resin. Alternatively, the reflection member 50 may beformed by coating an energy-ray (for example, ultraviolet ray) curingresin onto a base made of, for example, PET or the like, and thentransferring the shapes onto the energy-ray curing resin. Here, examplesof thermosetting resins may include a polycarbonate resin, an acrylicresin such as PMMA (a polymethyl methacrylate resin), a polyester resinsuch as polyethylene terephthalate, an amorphous copolymer polyesterresin such as MS (a copolymer of methyl methacrylate and styrene), apolystyrene resin, and a polyvinyl chloride resin. Moreover, in a caseof transferring the shape onto an energy-ray (for example, ultravioletray) curing resin, the base may be glass.

The optical sheet 60 may be provided on the light-emission surface (thefront surface) 40B side of the light guide plate 40, and may include,for example, a diffusion plate, a diffusion sheet, a lens film, apolarized light separation sheet, and so forth. FIG. 11 represents onlyone of these plural optical sheets 60. By providing the optical sheet 60as mentioned above, it is possible to allow light emitted obliquely fromthe light guide plate 40 to rise in the front direction, leading tofurther enhanced front luminance.

FIG. 12 illustrates an arrangement relation of the light source 10, theluminescent body 20, the wavelength selective filter 30, and the lightguide plate 40 illustrated in FIG. 11, representing a cross-section thatincludes a light-emission center 10A of the light source 10 and isvertical to the light-incident surface 40A.

The light source 10 may be disposed facing the light-incident surface40A of the light guide plate 40. Between the light source 10 and thelight-incident surface 40A, the container 22 accommodating theluminescent body 20 and the wavelength selective filter 30 may bedisposed. The light source 10, the container 22, and the wavelengthselective filter 30 may be held by, for example, a fixing member (aholder) 70. The reflection member 50 is laid on the bottom surface 40Dside of the light guide plate 40.

The luminescent body disposed region 21 may preferably cross a region 51surrounded by optical paths of light v31 and v32 that enters edges (anupper edge 40E and a lower edge 40F) of the light-incident surface 40Afrom the light source 10, and by the light-incident surface 40A. Theluminescent body disposed region 21 may preferably extend to an outerregion S2 beyond the region 51. By providing the luminescent body 20 inthis way, it is possible to enhance color uniformity in a plane.

The container 22 and the accommodating section 23 may be configuredsimilarly to those of the first embodiment.

The fixing member 70 may be configured of a high reflectionpolycarbonate resin, a polyamide-based resin (for example, “Genestar(trademark)” available from Kuraray Co. Ltd.), or the like. The fixingmember 70 may include, for example, a first fixing section 71, a secondfixing section 72, and a third fixing section 73. The first fixingsection 71 holds the light source 10. The second fixing section 72 andthe third fixing section 73 hold the container 22 of the luminescentbody 20.

The first fixing section 71 may be a portion to which the light sourcesubstrates 12 on which the light source 10 is mounted are attached. Thefirst fixing section 71 may face the light-incident surface 40A. Acenter portion of the first fixing section 71 may be provided with anopening 71C that penetrates the first fixing section 71 from an outersurface 71A to an inside surface 71B. On the outer surface 71A side ofthe opening 71C, a seat section 71D is provided by allowing a peripheryof the opening 71C to be recessed in a tiered shape. Accordingly, thelight source substrates 12 are fixed to the seat section 71D, allowingthe package 11 with the light source 10 mounted thereon to fit looselyin the opening 71C. It is to be noted that the seat section 71D may beomitted depending on a size of the light source substrates 12. Moreover,part or all of the inside surface 71B may be preferably an inclinedplane, in order to improve efficiency of utilizing light from the lightsource 10.

The second fixing section 72 and the third fixing section 73 areconfigured to hold an upper end and a lower end of the container 22 ofthe luminescent body 20 between them and to fix the container 22 inorder to prevent displacement in position or orientation of thecontainer 22. The second fixing section 72 and the third fixing section73 may extend, for example, from an upper end and an lower end of thefirst fixing section 71 in a direction substantially perpendicular tothe first fixing section 71. Accordingly, a cross-sectional shape of thefirst fixing section 71 to the third fixing section 73 may form, forexample, three sides of a rectangle. The upper end and the lower end ofthe container 22 may be held by, for example, projections for fixing(not illustrated) provided on the second fixing section 72 and the thirdfixing section 73. It is to be noted that the upper end and the lowerend of the container 22 may be fixed by other methods, for example, witha double-sided adhesive tape.

Further, between a tip portion of the second fixing section 72 and a tipportion of the third fixing section 73, an end of the light guide plate40 and an end of the reflection member 50 may be interposed and held. Itis to be noted that, between the second fixing section 72 and the thirdfixing section 73, at least the upper end and the lower end of thecontainer 22 may be interposed. The end of the light guide plate 40 andthe end of the reflection member 50 may be held by other members (whichwill be described later).

It is to be noted that, on an outer side of the fixing member 70 asdescribed above, in particular in a periphery of the light source 10, anundepicted heat dissipation member (a heat spreader) may be attached.Further, the entirety of the illumination device 2 including the lightsource 10 to the fixing member 70 and the heat dissipation member (notillustrated) may be accommodated in an undepicted casing (notillustrated in FIGS. 11 and 12, refer to a rear casing 124 in FIG. 18,for example).

In the illumination device 3, as illustrated in FIG. 13, the lightsource 10 generates the light v11, v12, and v13 of the first wavelength.The light v11 to v13 passes through the wavelength selective filter 30and enters the container 22. Here, the wavelength selective filter 30 isconfigured to transmit the light v11 to v13 of the first wavelength andto reflect the light v21 of the second wavelength. This allows the lightv11 to v13 of the first wavelength generated from the light source 10 totransmit the wavelength selective filter 30 with little attenuation, toenter the container 22, and to travel toward the luminescent body 20.

The light v11 and v12 that enters the container 22 but does not collidewith the luminescent body 20 passes through the container 22 and entersthe light guide plate 40. Since the bottom surface 40D of the lightguide plate 40 is provided with the pattern 41 having irregularreflection characteristics, the light v12 is reflected by the pattern41, travels toward an upper portion of the light guide plate 40, and isemitted through the light-emission surface 40B. The light v11 is totallyreflected by the light-emission surface 40B of the light guide plate 40before reaching the pattern 41, travels toward the bottom surface 40D,is reflected by the pattern 41, and is emitted through the lightemission surface 40B. The light thus emitted passes through the opticalsheet 50 and is observed as light emission.

On the other hand, the light v13 that enters the container 22 andcollides with the luminescent body 20 is wavelength-converted by theluminescent body 20, and becomes the light v21 and v22 of the secondwavelength.

The light v21 that collides with the luminescent body 20 and is emittedforward A1F passes through the container 22, enters the light-incidentsurface 40A of the light guide plate 40, is reflected by the pattern 41,and is emitted through the light-emission surface 40B. The emitted lightpasses through the optical sheet 50 and is observed as light emission.

On the other hand, the light v22 also occurs that collides with theluminescent body 20 and is emitted rearward MR. Here, the wavelengthselective filter 30 is configured to transmit the light v11 and v12 ofthe first wavelength and to reflect the light v21 and v22 of the secondwavelength. This allows the light v22 to be reflected by the wavelengthselective filter 30, is radiated forward A1F as the reflected light v23,passes through the container 22, and enters the light-incident surface40A of the light guide plate 40. The light v23 is reflected by thepattern 41, and is emitted through the light-emission surface 40B. Theemitted light passes through the optical sheet 50, is observed as lightemission, and is utilized effectively.

Moreover, since the light source 10 is a point light source as mentionedabove, the light generated from the light source 10 extends 360°omnidirectionally from the light-emission center 10A. As illustrated inFIG. 14, since the luminescent body disposed region 21 and thelight-incident surface 40A are horizontally elongated, the horizontalextension of light is unlikely to be a problem in particular. On theother hand, there is a possibility that part of the light extendingvertically is deviated above from the upper edge 40E or below from thelower edge 40F of the light-incident surface 40A.

Here, the luminescent body disposed region 21 crosses, as illustrated inFIG. 12, the region 51 surrounded by the optical paths of the light v31and v32 that enters the edges (the upper edge 40E and the lower edge40F) of the light-incident surface 40A from the light source 10, and bythe light-incident surface 40A. In other words, the luminescent bodydisposed region 21 is across (crosses) the region 51 in a directionparallel to the light-incident surface 40A. Accordingly, it is possibleto allow light that travels in the region 51 and enters thelight-incident surface 40A to be wavelength-converted by the luminescentbody 20.

Further, the luminescent body disposed region 21 extends to the outerregion S2 beyond the region 51. In other words, the luminescent bodydisposed region 21 is provided to protrude from the region 51 and tooverhang the outer region S2. Accordingly, it is possible to allow lightthat is emitted from the light source 10, extends vertically, andtravels outside of the region 51 to be captured to some extent by theluminescent body 20 and to be wavelength-converted. Therefore, in theillumination device 2, less light, out of the light from the lightsource 10, fails to pass through the luminescent body disposed region21, or fails to be wavelength-converted by the luminescent body 20. Thisleads to enhanced color uniformity in a plane.

As described above, in the present embodiment, similarly to the firstembodiment, the wavelength selective filter 30 is provided on thelight-incident side 20A of the luminescent body 20. The wavelengthselective filter 30 is configured to transmit the light v11 and v12 ofthe first wavelength and to reflect the light v21 of the secondwavelength. Hence, it is possible to improve efficiency of utilizinglight.

Moreover, the luminescent body disposed region 21 crosses the region S1surrounded by the optical paths of the light v1 and v2 that enters theedges (the upper edge 40E and the lower edge 40F) of the light-incidentsurface 40A from the light source 10, and by the light-incident surface40A. The luminescent body disposed region 21 extends to the outer regionS2 beyond the region S1. Hence, it is possible to reduce the light, outof the light from the light source 10, that fails to pass through theluminescent body disposed region 21, or fails to be wavelength-convertedby the luminescent body 20, leading to enhanced color uniformity in aplane.

MODIFICATION EXAMPLE 2

It is to be noted that, in the above-described second embodiment,description has been given on a case that the illumination device 3includes, as its main part, the illumination device 1 according to thefirst embodiment. However, as illustrated in FIG. 15, it is possible toconfigure an illumination device 4 that includes, as its main part, theillumination device 2 according to the second embodiment and to allowthe surface 22C that faces the light source 10 of the container 22 to becurved convexly toward the light source 10.

(Fourth Embodiment)

FIG. 16 illustrates an appearance of a display device 101 according to afourth embodiment of the present embodiment. The display device 101 maybe used as, for example, a thin television set, and may have aconfiguration in which a plate-shaped main body part 102 for imagedisplay is supported by a stand 103. It is to be noted that the displaydevice 101 may be used as a stationary type placed on a horizontal planesuch as a floor, a shelf, or a table in a state that the stand 103 isattached to the main body part 102. However, the display device 101 maybe used as a wall-mounted type in a state that the stand 103 is removedfrom the main body part 102.

FIG. 17 illustrates, in an exploded manner, the main body part 102illustrated in FIG. 16. The main body part 102 may include, for example,a front exterior member (a bezel) 111, a panel module 112, and a rearexterior member (a rear cover) 113 in this order from the front surfaceside (the observer side). The front exterior member 111 may be aframe-shaped member that covers a front periphery of the panel module112, and may include a pair of speakers 114 disposed in its lower part.The panel module 112 may be fixed to the front exterior member 111. Onits back surface, a power source substrate 115 and a signal substrate116 may be mounted, and a bracket 117 may be fixed. The bracket 117 maybe provided for fitting of a wall-mounting bracket, mounting ofsubstrates or the like, and attachment of the stand 103. The rearexterior member 113 may cover the back surface and side surfaces of thepanel module 112.

FIG. 18 illustrates, in an exploded manner, the panel module 112illustrated in FIG. 16. The panel module 112 may include, for example, afront casing (a top chassis) 121, a liquid crystal panel 122, a framemember (a middle chassis) 80, the optical sheet 60, the light guideplate 40, the reflection member 50, a rear casing (the back chassis)124, a balancer substrate 125, a balancer cover 126, and a timingcontroller substrate 127 in this order from the front surface side (theobserver side).

The front casing 121 is a metal component that covers a front peripheryof the liquid crystal panel 122. The liquid crystal panel 122 mayinclude, for example, a liquid crystal cell 122A, a source substrate122B, and a flexible substrate 122C such as a COF (Chip On Film) thatconnects these. The frame member 123 may be a frame-shaped resincomponent that holds the liquid crystal panel 122 and the optical sheet50. The rear casing 124 may be a metal component made of iron (Fe) orthe like that accommodates the liquid crystal panel 122, theintermediate casing 123, and the illumination device 3. The balancersubstrate 125 is configured to control the illumination device 3, andmay be mounted on a back surface of the rear casing 124 and covered bythe balancer cover 126, as illustrated in FIG. 16. The timing controllersubstrate 127 may be also mounted on the back surface of the rear casing124.

In the display device 101, light from the illumination device 3 isselectively transmitted by the liquid crystal panel 122, allowing imagedisplay to be performed. Here, as described in the third embodiment, theillumination device 3 with an enhanced efficiency of utilizing light isprovided. This contributes to improvement in brightness of the displaydevice 101 and reduction in power consumption.

It is to be noted that, in the above-described embodiment, descriptionhas been given on a case that the display device 101 includes theillumination device 3 according to the third embodiment. However, itgoes without saying that the display device 101 may include theillumination device 4 according to the modification example 2 instead ofthe illumination device 3 according to the third embodiment.

APPLICATION EXAMPLES

In the following, description will be given on application examples ofthe display device 101 as described above to electronic apparatuses.Examples of electronic apparatuses may include a television set, adigital camera, a notebook personal computer, a mobile terminal devicesuch as a mobile phone, a video camera, or the like. In other words, thedisplay device as described above may be applied to an electronicapparatus in various fields that is configured to display an image or apicture based on a picture signal input from outside or generatedinside.

Application Example 1

FIGS. 19 and 20 illustrate an appearance of an electronic book 210 towhich the display device 101 according to the above-described exampleembodiment is applied. The electronic book 210 may include, for example,a display section 211 and a non-display section 212. The display section211 is configured of the display device 101 according to theabove-described example embodiment.

Application Example 2

FIGS. 21 and 22 illustrate an appearance of a smart phone 220 to whichthe display device 101 according to the above-described exampleembodiment is applied. The smart phone 220 may include, for example, adisplay section 221 and an operation section 222 on a front side, and acamera 223 on a back side. The display section 221 is configured of thedisplay device 101 according to the above-described example embodiment.

Application Example 4

FIGS. 23 and 24 illustrate an appearance of a digital camera 240 towhich the display device 101 according to the above-described exampleembodiment is applied. The digital camera 240 may include, for example,a lighting section for flash lighting 241, a display section 242, a menuswitch 243, and a shutter button 244. The display section 242 isconfigured of the display device 101 according to the above-describedexample embodiment.

Application Example 5

FIG. 25 illustrates an appearance of a notebook personal computer 250 towhich the display device 101 according to the above-described exampleembodiment is applied. The notebook personal computer 250 may include,for example, a main body 251, a keyboard 252 for input operations ofcharacters and the like, and a display section 253 for image display.The display section 253 is configured of the display device 101according to the above-described example embodiment.

Application Example 6

FIG. 26 illustrates an appearance of a video camera 260 to which thedisplay device 101 according to the above-described example embodimentis applied. The video camera may include, for example, a main body 261,a lens 262 for photographing an object, which is provided on a frontside face of the main body 261, a start/stop switch 263 inphotographing, and a display section 264. The display section 264 isconfigured of the display device 101 according to the above-describedexample embodiment.

Application Example 7

FIGS. 27 and 28 illustrate an appearance of a mobile phone 270 to whichthe display device 101 according to the above-described exampleembodiment is applied. The mobile phone 270 may have a configuration,for example, in which an upper casing 271 and a lower casing 272 arelinked by a connection section (a hinge section) 273, and may include adisplay 274, a sub-display 275, a picture light 276, and a camera 277.The display 274 or the sub-display 275 is configured of the displaydevice 101 according to the above-described example embodiment.

Application Examples of Illumination Devices

FIGS. 29 and 30 illustrate an appearance of an illumination apparatusfor desktop use, to which the illumination devices 1 to 4 according tothe above-described example embodiments are applied. In the illuminationapparatus 310, for example, an illumination section 313 may be attachedto a support 312 provided on a base 311. The illumination section 313 isconfigured of one of the illumination devices 1 to 4 according to theabove-described example embodiments. The illumination section 313 may betake any shape, for example, a tubular shape illustrated in FIG. 29 or ashape of a curved plane illustrated in FIG. 30, by allowing the lightguide plate 40 to take a curved shape.

FIG. 31 illustrates an appearance of an illumination apparatus forindoor use, to which the illumination devices 1 to 4 according to theabove-described example embodiments are applied. The illuminationapparatus 320 may include, for example, an illumination section 321 thatis configured of one of the illumination devices 1 to 4 according to theabove-described example embodiments. The illumination section 321 may bedisposed on a ceiling 322A of a building in appropriate number and atappropriate intervals. It is to be noted that the illumination section321 may be placed at any locations depending on usages, for example, ona wall 322B or on a floor (not illustrated), without limitation to theceiling 322A.

In the illumination apparatuses 310 and 320, illumination is carried outwith the light from the illumination devices 1 to 4. Here, as describedabove in the example embodiments, the illumination devices 1 to 4 withenhanced efficiency of utilizing light are provided. This contributes toimprovement in brightness and reduction in power consumption.

Although description has been made by giving the example embodiments,the contents of the present disclosure are not limited to theabove-mentioned example embodiments and may be modified in a variety ofways. For example, a material and a thickness of each layer as describedin the above-mentioned example embodiments are not limitative, but othermaterials and other thicknesses may be adopted.

Moreover, for example, in the above-described example embodiments,description has been made on a case that the light source 10 is an LED.However, the light source 10 may be configured of a semiconductor laseror the like.

Furthermore, for example, in the above-described example embodiment,description has been given on specific configurations of theillumination devices 1 to 4, and the display device 101 (a televisionset). However, it is not necessary to include all the components, andanother component or other components may be further provided.

It is to be noted that the contents of the present technology may havethe following configurations.

(1) An illumination device including:

-   -   a light source that is configured to generate light of a first        wavelength;    -   a luminescent body that is configured to wavelength-convert the        light of the first wavelength to light of a second wavelength,        the second wavelength being different from the first wavelength;        and a wavelength selective filter that is provided on a        light-incident side of the luminescent body, the wavelength        selective filter being configured to transmit the light of the        first wavelength and to reflect the light of the second        wavelength.

(2) The illumination device according to (1),

-   -   wherein the luminescent body includes a fluorescent substance.

(3) The illumination device according to (2),

-   -   wherein the luminescent body includes a quantum dot.

(4) The illumination device according to (2),

-   -   wherein the luminescent body includes a sulfide phosphor.

(5) The illumination device according to any one of (1) to (4),including a container that accommodates the luminescent body,

-   -   wherein the wavelength selective filter is provided on an outer        surface on a light-incident side of the container.

(6) The illumination device according to (5),

-   -   wherein the container includes, in an inside of the container,        an accommodating section of the luminescent body, and    -   a width of the wavelength selective filter is larger than a        width of the accommodating section.

(7) The illumination device according to (6),

-   -   the container has a shape of a cuboid and is disposed with a        surface of the cuboid facing the light source, and    -   the wavelength selective filter is provided at least on a        surface that faces the light source of the container.

(8) The illumination device according to (7),

-   -   wherein the surface that faces the light source of the container        is curved convexly toward the light source.

(9) The illumination device according to (7) or (8),

-   -   wherein the wavelength selective filter extends, beyond the        surface that faces the light source of the container, on at        least part of a surface adjacent to the surface that faces the        light source of the container.

(10) The illumination device according to any one of (1) to (9),

-   -   wherein the light source is a blue light source.

(11) The illumination device according to (10),

-   -   wherein the luminescent body is configured to wavelength-convert        blue light to red light or green light.

(12) The illumination device according to any one of (1) to (11),including an optical member, the optical member including alight-incident surface that faces the luminescent body.

(13) The illumination device according to (12),

-   -   wherein the optical member is a light guide plate, and    -   the light-incident surface is an end surface of the light guide        plate.

(14) A display device provided with a liquid crystal panel and anillumination device on a rear side of the liquid crystal panel,

-   -   the illumination device including:        -   a light source that is configured to generate light of a            first wavelength;        -   a luminescent body that is configured to wavelength-convert            the light of the first wavelength to light of a second            wavelength, the second wavelength being different from the            first wavelength; and        -   a wavelength selective filter that is provided on a            light-incident side of the luminescent body, the wavelength            selective filter being configured to transmit the light of            the first wavelength and to reflect the light of the second            wavelength.

This application claims the benefit of Japanese Priority PatentApplication JP 2012-247262 filed on Nov. 9, 2012, the entire contents ofwhich are incorporated herein by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. An illumination device comprising: a light source that is configuredto generate light of a first wavelength; a luminescent body that isconfigured to wavelength-convert the light of the first wavelength tolight of a second wavelength, the second wavelength being different fromthe first wavelength; and a wavelength selective filter that is providedon a light-incident side of the luminescent body, the wavelengthselective filter being configured to transmit the light of the firstwavelength and to reflect the light of the second wavelength.